Multivariate analysis on the relationship between radical scavenging activities and phenolic compounds of baijiu and its protective effect against LPS-induced inflammation in THP-1 cells

Abstract

In previous studies, three phenolic compounds (vanillin, 4-methylguaiacol, and 4-ethylguaiacol) were identified in baijiu, and confirmed to possess antioxidant activity in vitro. However, the distribution of phenolic compounds in baijiu, and their associations with the functionality of this regimen have not been previously reported. In the present work, the antioxidant capacity and anti-inflammatory effect of baijiu were evaluated by DPPH•, ABTS•+, ELISA, and real-time PCR assays. The concentrations of vanillin, 4-methylguaiacol, and 4-ethylguaiacol (bioactive phenolic compounds) in 103 baijiu samples were confirmed by liquid-liquid extraction (LLE) combined with gas chromatography-mass spectrometry (GC-MS). Baijiu exhibited DPPH• and ABTS•+ scavenging activities, which positively correlated with the concentrations of vanillin, 4-methylguaiacol, and 4-ethylguaiacol. Moreover, ELISA and real-time PCR assays demonstrated that baijiu could relieve inflammation caused by LPS through the inhibition of NF-κB and AP-1 expressions, induction of Nrf2 expression, and repression of inflammatory cytokine secretion. These findings lay the foundation for further investigation on the health benefits of baijiu and its bioactive components by animal and human studies.